PURPOSE: Psychological factors have been identified as an important factor underlying physical activity behavior in adults. However, the extent to which these psychological factors impact physical activity behavior remains poorly understood. The aim of the study was to examine the association between psychological stress and physical inactivity in subsets of data from the Korean Genome and Epidemiology Study (KoGES). METHODS: 69,219 participants (24,025 men) aged 40-69 were drawn from urban and rural community based cohort studies, which are subprojects of KoGES. We analyzed the association between psychological stress and physical inactivity using logistic regression. Cox’s proportional hazard regression analysis was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of exercise behavior changes according to psychological stress level changes. RESULTS: Compared to the healthy stress group, the likelihood of physical inactivity was increased in high-risk stress group (men OR=1.88, 95% CI 1.63-2.17, p<.001, women OR=2.24 95% CI, 2.04-2.47, p<.001). During the mean follow-up period of 4.6 years, compared to the sustained healthy stress, the group with increased stress level was at a higher risk of remaining physical inactive (men HR=2.16, 95% CI 1.24-3.69, p<.001, women HR=1.54, 95% CI 1.12-4.06, p<.001), and the risk becoming physical inactive (men HR=2.33, 95% CI 1.33-4.09, p=.003, women HR=2.13, 95% CI 1.12-4.06, p=.021). CONCLUSIONS: These results suggest that the psychological stress could be barrier of exercise participation. Management of psychological stress should be considered in the strategy for promoting exercise participation in the community.